>The core of the issue is that the potential IQ improvements >of FX over DX seem to be narrowing. That will make FX more of >a niche format than it is now, but I don't see FX going away >any time soon.
I think the difference in IQ improvements is most likely staying on an equal footing between FX and DX. The introduction of the next generation of DX body's has happened before the introduction of the next generation of FX bodies so the gap in performance is percieved to be shrinking. The proof will be seen when the next generation of FX bodies is introduced sometime in the not too distant future. Good Luck and Enjoy your Nikons!